1. Field of the Invention
The present invention relates to a method and system for managing a process of image data acquired by a computed radiography (CR) technique and additional information added to the image data.
2. Description of the Related Art
In recent years, a medical image diagnosis by a CR technique using an imaging plate (to be referred to simply as an IP hereinafter) has become popular. FIG. 1 shows an example of a system based on the CR technique. This system comprises X-ray radiographing apparatus 1, image reading apparatus 2, image processing apparatus 3, and image reproduction and recording apparatus 4. X-ray radiographing apparatus 1 has an X-ray tube for radiating X-rays onto an object to be examined, and a first recording medium (e.g., an IP.) for accumulating X-rays passing through the object as energy. Image reading apparatus 2 performs scanning using excited light having a wavelength of 500 to 800 nm on the IP to excite the energy accumulated on the IP, thereby causing the IP to radiate light having a wavelength of 300 to 700 nm. The light radiated from the IP within a predetermined wavelength range is received by a photodetector (e.g., a photomultiplier, photodiode, or the like). After an image is read by image reading apparatus 2, image processing apparatus 3 subjects the image to frequency enhancement processing and gray scale processing. The processed result is stored in an image memory or the like. Image reproduction and recording apparatus 4 sequentially reads out image data stored in the image memory. The image data is converted to an analog signal by a D/A converter, and the analog signal is converted to a light signal using a recording light source. The light signal is radiated onto a second recording medium (e.g., a radiographing film) through a lens system, thus forming a corresponding image on the recording medium. The image formed on the second recording medium by the CR system can be used for medical diagnosis of the examined object.
The detailed arrangement of the above-mentioned CR system will be described below.
In FIG. 2, subsystem 5 is constituted by image reading apparatus 2, image processing and control apparatus 10, image monitor 7, image reproduction and recording apparatus 4, and a plurality of IP information input apparatuses 9a, . . . , 9n. IP cassette 6 having an IP used for a radiographing operation by X-ray radiographing apparatus 1 shown in FIG. 1 is set in image reading apparatus 2. Each IP is taken out from IP cassette 6, and image data stored in this IP is read out in accordance with image reading conditions determined by in advance IP information (to be described later), including radiograph information and patient information input from IP information input apparatuses 9a, . . . , 9n. The image data is input to image processing and control apparatus 10, and is subjected to frequency enhancement processing, gray scale processing, and the like.
The image data processed by image processing and control apparatus 10 is displayed on image monitor 7 to be observed by an operator, and is transferred to image reproduction and recording apparatus 4. Image reproduction and recording apparatus 4 records the image data on recording medium 8. IP information input by IP information input apparatuses 9a, . . . , 9n is recorded on recording medium 8.
The image data displayed on image monitor 7 is normally used after the above-mentioned processing for a radiographic technician to determine whether or not positioning of IP cassette 6 used for X-ray radiographing with respect to the object is appropriate. If the positioning of IP cassette 6 with respect to the object is not appropriate, a radiographing operation is restarted.
The image data input to image reproduction and recording apparatus 4 is converted to the analog signal by the D/A converter, as described above, and the analog signal is converted to a light signal by the recording light source. Thereafter, an X-ray image is formed on recording medium 8 using the light signal. Recording medium 8 is fed to an automatic developing machine (not shown) and is subjected to development and fixing, thus obtaining a hard copy of the X-ray image.
The above system is equipped in, e.g., a CR room. Image reading apparatus 2, image processing and control apparatus 10, and image reproduction and recording apparatus 4 are synchronously operated. Their operation speed is determined by the image reading apparatus 2 which has the slowest operation speed.
The image processing and control apparatus 10 operates at a speed which is at least two times the operation speed of the image reading apparatus 2. Since the operation speed of the image reading apparatus 2 is dependent upon the physical characteristics of the IP (response of reading), the operation speed cannot be improved.
In the conventional system, in order to improve a throughput, e.g., to increase the number of IPs to be processed per hour, a system as shown in FIG. 1 is extended, as needed.
However, when a plurality of systems are extended, IP information is input to the subsystem capable of reading image data, as shown in FIG. 2, and a radiographed IP must be input to and processed by the corresponding subsystem. More specifically, since radiograph information included in the IP information changes for every radiographing operation, an operator must determine the subsystem to which the IP information input apparatus, equipped near the X-ray radiographing apparatus, is currently connected, and must input the IP to the image processing and control apparatus of the selected subsystem without failure.
If the IP is processed in another subsystem, the IP information must be re-input, resulting in a cumbersome operation.
In a plurality of X-ray radiographing apparatuses, when a radiographing operation is performed too frequently and beyond the processing capacity of a given subsystem, the radiographed IPs form a queue for processing. More specifically, if unprocessed IPs are concentrated on a given subsystem, there is a long wait time for processing. This is true even if the wait time of other subsystems is short because IP processing cannot be independently performed in other subsystems. Therefore, if a plurality of subsystems are extended, the throughput of the system as a whole cannot be satisfactorily improved since a variation in wait time occurs.
Additionally, if an image reading apparatus of a subsystem malfunctions and cannot read an image, IPs must be processed in another subsystem. However, since IP information input may occur before the apparatus malfunctions IP information cannot be used by another subsystem, and the IP information must be re-input in order to process IPs in a subsystem capable of reading.
As described above, a demand has arisen for an apparatus which can improve the throughput of a system as a whole by efficiently processing IPs.